ANSI B16.5 Forged Flanges
Class 300 Flange Dimensions
ASME B16.5
Class 300 flanges provide moderate pressure capability for process piping in refineries and chemical plants. All dimensions are in inches.
| NPS | Flange OD | Thickness (min) | RF Diameter | Bolt Circle | # Bolts | Bolt Dia. | Hub Dia. | WN Length | Bore |
|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 3.75 | 0.56 | 1.38 | 2.62 | 4 | 1/2 | 1.19 | 2.06 | 0.88 |
| 3/4 | 4.62 | 0.62 | 1.69 | 3.25 | 4 | 5/8 | 1.50 | 2.25 | 1.09 |
| 1 | 4.88 | 0.69 | 2.00 | 3.50 | 4 | 5/8 | 1.94 | 2.44 | 1.36 |
| 1-1/4 | 5.25 | 0.75 | 2.50 | 3.88 | 4 | 5/8 | 2.31 | 2.56 | 1.70 |
| 1-1/2 | 6.12 | 0.81 | 2.88 | 4.50 | 4 | 3/4 | 2.56 | 2.69 | 1.97 |
| 2 | 6.50 | 0.88 | 3.62 | 5.00 | 8 | 5/8 | 3.06 | 2.75 | 2.44 |
| 2-1/2 | 7.50 | 1.00 | 4.12 | 5.88 | 8 | 3/4 | 3.56 | 3.00 | 2.94 |
| 3 | 8.25 | 1.12 | 5.00 | 6.62 | 8 | 3/4 | 4.25 | 3.12 | 3.57 |
| 3-1/2 | 9.00 | 1.19 | 5.50 | 7.25 | 8 | 3/4 | 4.69 | 3.19 | 4.07 |
| 4 | 10.75 | 1.25 | 6.19 | 9.25 | 8 | 3/4 | 5.31 | 3.38 | 4.57 |
| 5 | 13.00 | 1.38 | 7.31 | 11.00 | 8 | 3/4 | 6.44 | 3.88 | 5.66 |
| 6 | 14.00 | 1.44 | 8.50 | 11.75 | 12 | 3/4 | 7.56 | 4.19 | 6.72 |
| 8 | 16.50 | 1.62 | 10.62 | 13.75 | 12 | 7/8 | 9.69 | 4.62 | 8.72 |
| 10 | 20.00 | 1.88 | 12.75 | 17.00 | 16 | 1 | 11.75 | 5.12 | 10.88 |
| 12 | 22.00 | 2.00 | 15.00 | 19.25 | 16 | 1-1/8 | 13.75 | 5.62 | 12.88 |
| 14 | 23.75 | 2.12 | 16.25 | 20.75 | 20 | 1-1/8 | 15.00 | 6.00 | 14.14 |
| 16 | 27.00 | 2.25 | 18.50 | 24.00 | 20 | 1-1/4 | 17.00 | 6.12 | 16.16 |
| 18 | 29.25 | 2.38 | 21.00 | 25.75 | 24 | 1-1/4 | 19.00 | 6.75 | 18.18 |
| 20 | 32.00 | 2.50 | 23.00 | 28.50 | 24 | 1-1/4 | 21.00 | 7.00 | 20.20 |
| 24 | 37.00 | 2.75 | 27.25 | 33.00 | 24 | 1-1/2 | 25.00 | 8.00 | 24.25 |
